From owner-freebsd-arch  Fri Oct 26 15:34:10 2001
Delivered-To: freebsd-arch@freebsd.org
Received: from mailman.zeta.org.au (mailman.zeta.org.au [203.26.10.16])
	by hub.freebsd.org (Postfix) with ESMTP id 0C31E37B405
	for <arch@FreeBSD.ORG>; Fri, 26 Oct 2001 15:34:06 -0700 (PDT)
Received: from bde.zeta.org.au (bde.zeta.org.au [203.2.228.102])
	by mailman.zeta.org.au (8.9.3/8.8.7) with ESMTP id IAA16269;
	Sat, 27 Oct 2001 08:33:57 +1000
Date: Sat, 27 Oct 2001 08:33:00 +1000 (EST)
From: Bruce Evans <bde@zeta.org.au>
X-X-Sender:  <bde@delplex.bde.org>
To: Poul-Henning Kamp <phk@critter.freebsd.dk>
Cc: Peter Wemm <peter@wemm.org>, <arch@FreeBSD.ORG>
Subject: Re: 64 bit times revisited.. 
In-Reply-To: <23015.1004077694@critter.freebsd.dk>
Message-ID: <20011027081803.N90305-100000@delplex.bde.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: owner-freebsd-arch@FreeBSD.ORG
Precedence: bulk
List-ID: <freebsd-arch.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo@FreeBSD.ORG?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo@FreeBSD.ORG?subject=subscribe%20freebsd-arch>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20freebsd-arch>
X-Loop: FreeBSD.ORG

On Fri, 26 Oct 2001, Poul-Henning Kamp wrote:

> BUT, i would like to point out a problem in the other direction:
>
> We are now routinely talking about GHz+ CPUs, but struct timespec
> can only do nanosecond resolution and arithmetic on timeval and
> timespec sux badly.
>
> I would like for us to introduce a new format of timestamps:
>
> 	struct time$something {
> 		time_t	  tx_sec;		/* 64bit */
> 		uint_64_t tx_fsec;		/* binary fraction of second */;
> 	}
> ...
> Comments ?

    I happen to think that such micro-optimizations turn out to be
    much more trouble than they are worth. -- phk

All final consumers of timestamps need decimal fractions, since syscall
interfaces only pass timevals and timespecs.  I suspect the above change
won't make much difference to the amount of timefoo arithmetic, because
most of it is for final consumers.

Bruce


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-arch" in the body of the message